now you got me: where to check the default initiator setting? I tried to find the info in connection to the iscsi and see the connection status at the open-e status info page:

I did a manuel discover and connect
[root@PCCO-XEN01 ~]# iscsiadm -m discovery -t st -p 10.33.2.12
10.33.2.12:3260,1 iqn.2011-11:dss-lite.target0

then logged myself in
[root@PCCO-XEN01 ~]# iscsiadm -m node -L all
Logging in to [iface: default, target: iqn.2011-11:dss-lite.target0, portal: 10.33.2.12,3260]
Login to [iface: default, target: iqn.2011-11:dss-lite.target0, portal: 10.33.2.12,3260]: successfu

The open-e showed the following connection:
Initiator name: iqn.2011-11.com.example:7beceb9f

After logging off, I tried to connect to the target
[root@PCCO-XEN01 ~]# iscsiadm -m node -T iqn.2011-11:dss-lite.target0 -p 10.33.2.12 -l
Logging in to [iface: default, target: iqn.2011-11:dss-lite.target0, portal: 10.33.2.12,3260]
Login to [iface: default, target: iqn.2011-11:dss-lite.target0, portal: 10.33.2.12,3260]: successfull

another probe at the XEN results in the same error:

[root@PCCO-XEN01 ~]# xe sr-probe type=lvmoiscsi device-config:target=10.33.2.12 device-config:targetIQN=iqn.2011-11:dss-lite.target0
There was an SR backend failure.
status: non-zero exit
stdout:
stderr: Traceback (most recent call last):
File "/opt/xensource/sm/LVMoISCSISR", line 378, in ?
SRCommand.run(LVHDoISCSISR, DRIVER_INFO)
File "/opt/xensource/sm/SRCommand.py", line 244, in run
sr = driver(cmd, cmd.sr_uuid)
File "/opt/xensource/sm/SR.py", line 128, in __init__
self.load(sr_uuid)
File "/opt/xensource/sm/LVMoISCSISR", line 75, in load
iscsi = driver(self.original_srcmd, sr_uuid)
File "/opt/xensource/sm/SR.py", line 128, in __init__
self.load(sr_uuid)
File "/opt/xensource/sm/util.py", line 1135, in transform
return func(inst, *args, **kwargs)
File "/opt/xensource/sm/ISCSISR.py", line 167, in load
self._initPaths()
File "/opt/xensource/sm/ISCSISR.py", line 170, in _initPaths
self._init_adapters()
File "/opt/xensource/sm/ISCSISR.py", line 236, in _init_adapters
self.devs = scsiutil.cacheSCSIidentifiers()
File "/opt/xensource/sm/scsiutil.py", line 129, in cacheSCSIidentifiers
line = "NONE %s %s %s %s 0 %s" % \
IndexError: list index out of range

I will see if I can get me some infos from the XEN Forums.
Thanks for your help.